U.S. Pat. No. 5,559,651 of Grantz et al, entitled "Magnetic Disc Storage System with Hydrodynamic Bearing," discloses a bearing cartridge for rotatably supporting a magnetic storage disc that utilizes fluid-dynamic bearings defined by spherical bearing cones and bearing seats. Spherical bearings are known to improve assembly and alignment tolerances in that they allow for greater angular misalignment of the bearing cone piece with respect to the bearing seat.
Conical bearing designs are also known wherein both the bearing seat and the bearing cone are conical in shape. Conical bearings improve the tilting stiffness of fluid-dynamic bearings and thereby resist radial and axial displacement greater than, for example, spherical bearings. However, conical bearings are more susceptible to angular misalignment, which can significantly affect the performance of the bearing.
The present invention is an attempt to maximize the advantages of spherical and conical bearings while at the same time minimizing their respective disadvantages.